Photographic developing method

ABSTRACT

A METHOD AND COMPOSITION FOR PROCESSING A SILVER HALIDE BLACK AND WHITE PHOTOGRAPHIC MATERIAL WHEREIN THE SILVER HALIDE GRAINS ARE LESS THAN 0.3 MICRON WHICH COMPRISES DEVELOPING THE PHOTOGRAPHIC MATERIAL WITH A DEVELOPING SOLUTION HYDROQUINONE (SUBSTITUTED OR UNSUBSTITUTED) AS THE MAIN DEVELOPING AGENT AND IMIDAZOLE IN A MINOR AMOUNT.

United States Patent Office 3,708,299 Patented Jan. 2, 1973 U.S. Cl.96-663 8 Claims ABSTRACT OF THE DISCLOSURE A method and composition forprocessing a silver halide black and white photographic material whereinthe silver halide grains are less than 0.3 micron which comprisesdeveloping the photographic material with a developing solutioncomprising hydroquinone (substituted or unsubstituted) as the maindeveloping agent and imidazole in a minor amount.

BACKGROUND OF THE INVENTION This invention relates to the processing ofsilver halide photographic materials and more particularly to developingsolution for fine grained photographic materials.

Description of prior art The desirable properties of processingprocedures for silver halide, Black and White photographic materialsreside in increased speed, high rate of development and fine grainedsilver image. The well known development accelerators are aminecompounds, such as alkylamines (U.S. Pat. No. 2,196,037), aralkylamines(U.S. Pat. No. 2,496,903; 2,515,147; 2,541,889), phenoxyalkylamines(U.S. Patent No. 2,482,546), heterocyclic alkylamines (U.S. Pat.2,605,183), morpholine and piperidine (U.S. Pat. No. 1,086,681). Theseamines, however, are poisonous, odoriferous and volatile, thusnecessitating careful handling. Furthermore, their concentration indeveloping solution is often diificult to keep constant. The increase inrate of development is observed to some extent by an addition of thesecompounds to the developing solution, but this effect is often negatedby the increase in fog formation. Furthermore, the deterioration in thegranularity of the developed silver is often observed.

SUMMARY OF THE INVENTION Therefore, the principal object of thisinvention is to provide an improved accelerator for the developingsolution, which is easily handled, capable of increasing the rate ofdevelopment and increasing the effective speed of the photographicmaterial without undesirable increase in fog and the deterioration inthe granularity of the developed silver.

Still another object of this invention is to provide a process foraccelerating the developing of the fine grained photographic materialswithout deterioration in the granularity of the developed silver.

The developing solution of this invention is applied to theblack-and-white photographic materials, especially to low sensitivitysilver halide photographic materials which require fine granularity andis generally used for the oflice works, documentary works, industrialworks, or reprographic works.

The present invention can be applied to telephotographic materials;lithographic materials (used for producing dots), phototypesettingmaterials, microfilms, microplates, materials for facsimile, materialsfor prints of scanned dots, materials for production of integral circuitmaster and photographic materials for astronomical study; thesephotographic materials are composed of extremely fine grained silverhalide and contain very small amounts of silver halide.

Therefore, these two features of the photographic materials providedifferent ways of development from that for the ordinary photographicmaterials.

For these materials, the granularity of the developed silver imageshould be adequately low throughout the development in the developmentof, e.g., fine grain silver halide emulsions as in the developingacceleration of this invention.

Detailed description of the invention Accordingly, the present inventionprovides a method of treating a photographic material which comprisedeveloping the materials with the developer containing imidazole andhydroquinone (substituted or unsubstituted) thus increasing the rate ofdevelopment or shortening the developing time, inhibiting the fogformation, increasing the effective sensitivity and making fine thedeveloped silver particles.

It has already been shown in U.S. Pat. No. 3,126,282 to add an imidazoleto the first developer for the reversible color film Whose emulsioncontains non-diifusible color coupler to increase the speed of the film.

However, the increase in speed of the black-and-white photographicmaterial to which this invention is applied by the imidazole is muchgreater than that of the reversible color film described in the U.S.lPat. 3,126,282. From the examples of the specification, the reversiblecolor film of this is considered to be composed of an emulsion of coarsesilver iodobromide particles, while the emulsion of the Black and Whitephotographic materials used in this invention contains finely dividedsilver halide particles.

That is to say, the process for developing the photographic materialcontaining fine grain silver halides according to this invention hasbeen made on a discovery that the increase in speed by an imidazoledepends on the size of the silver halide grain.

The fact that the developing of the photographic material with finegrain silver halides is accelerated by the imidazole when added to thedeveloping solution in an amount contemplated herein has been unknownand have not been heretofore shown in the prior art. The expression finegrained denotes a particle size of from 0.1 to 0.3 micron.

Preferred embodiments The developing solution exhibiting the aforesaidadvantageous effects with the addition of the imidizole contains atleast 120 parts/liter hydroquinone as the main developing agent and, inaddition, a conventional developer such as 1-phenyl-3-pyrazolidone orN-methyl-paminophenol. If necessary, an oxidation inhibitor, such as Nasulfite or ascorbic acid, a suitable pH buffer, such as boric acid,sodium hydroxide, sodium carbonate or sodium phosphate, a developinginhibitor such as potassium iodide or potassium bromide, an organic foginhibitor such as 6-nitro-benzimidazole or benzotriazole, and analdehyde such as formaldehyde or glutaraldehyde can be added to thedeveloping solution. The pH of this developing solution may be adjustedin a range between 8.5 and 12.0 and preferably 10 to 11. The amounts ofthe imidazole to be added to the developing solution vary with the typeof the photographic material employed and the pH of the developingsolution, but favorably in the range of between 0.5 part/liter andparts/liter. The finely divided silver halide is present in aconcentration of from 10-70 mg./100 cm. and preferably 20-50 mg./crn.

A better understanding of the present invention will be had from thefollowing examples which are merely illus- 4 trative and not limitativein nature. All parts are by weight Parts unless otherwise stated.N-methyl-p-aminophenol 5.0 Sodium sulfite 70.0 EXAMPLE 1 Hydroquinone2.0 The 8 types of photographic films (I)-(VIII) were ex- Sodiumcarbonate monohydrate 41.0 posed to light by sensitometer and subjectedto process of Potass um bromide 4.0 this invention; (I) commercialdirect X-ray film, (II) Po assium thlocyanate 1.6 high speed black andwhite negative film (ASA 100) for Potassium 1od1de (0.1% aq. solution)amateur use, (III) reversal color film (ASA 100) for (by vol.) 10.0amateur use, (IV) color negative film (ASA 100) for 10 Water to make 1liter. amateur use (V) black and white fine grain posifilm for (d) Thedevelo 1 ping so ution for the photographic film the cinematography,(VI) resographic film for photo- (IV) (developer for the color negativefilm). mechanical use, (VII) telephotographic film, (VIH) m1- Partscrofilm' Sodium hexamethaphosphate 1.4

The process of this invention was not effective for the BenzylalcoholVOL)" films (I)-(IV), but the test results were shown to be Sodiumsulfite 30 compared with those of the films (V)(VII). The mean Sodiumcarbonate 4L0 diameter of the silver halide grains in each of the photo-Sodium hydroxide L0 graphlc films were as follows: 4-amino 3methyl-N-ethyl-N-methane sulfon- Mean diameter of the amidethylanilinesulfate 5.0 Photographic film: silver particle, microns Potassiumbromide 0.5

I 1.4 Water to make 1 liter.

H (e) The developing solution for the photographic films III 0.9

W 10 (V)-(VIII):

""""""""""""""""""""""" D-l6 developing solution for the black and whiteVI 0 2 posifilm (Eastman Kodak).

This D-16 developer was also applied to the films VII 0 2 VIII (I) and(II), though they were processed by the developers (a) and (b), too. Inthe first series of the developing Each of the photographic film(I)-(VII) was subsolutions (a)-(e) imidazole was not added and thesecjected to the developing treatment with the suitable deond series 2.0parts/liter added. veloping solution below. The test results were shownin the following table:

Addition Relative of lmidasensitivity Photographic Developing conditionszole, (logarithmic films (developer, temp, time) g./l. sensitivity)Notes I Rendol, 24 C., 5min 0 2. 60 .I 2.0 2.65 Increase in iog,deterioration of the silver image.

II D76, 24 0., 6min 0 2. 20 11.... do 2.0 2.30 Deterioration oi thesilver image. III (0), 24 0., 6min 0 2. m dn 2. o 2. Do. 111 (c) 1 240., 6min 2.0 2. 45 IV ((1), 24 0., 10 min 0 2. 05 Iv o 2.0 2.10 I D-IG,24 0., 5 min 0 2. 45 T 2.3 22 Increase in tog, deterioration of thesilver image.

2.0 2:45 Deterioration oi the silver image.

1 (c) is a developing solution same as the (0) except for the lack ofpotassium thiocyanate.

(a) The developing solution for the photographic film PartsMono-methyl-p-amino phenol 4.0 Sodium sulfite (anhydride) Hydroquinone10 Sodium carbonate (anhydride) 53 Potassium bromide 2.5

Water to make one liter.

*Rendol developing solution (produced by Fuji Photo Film Co., Ltd.)

(b) The developing solution for the photographic film D-76 developingsolution (produced by Eastman Kodak Co., Ltd.).

(c) The developing solution for the photographic film (III) (firstdeveloper for the reversal color film):

*Mono-methyl-p-amino phenol-4.0 parts; sodium sulfite- (unhydride)60parts; hydr0quinone-10 parts; sodium carbonate(anhydride)-53 partspotassium bromide2.5 parts water to makeoue liter.

It is apparent from this table that the addition of imidazole is veryefiective for the emulsion of fine grained silver halide.

EXAMPLE 2 Commercial fine grain positive film for the cinematographycomposed of grained silver bromochloride-gelatinemulsion was subjectedto development with solution having following composition at 27 C.

Developing solution A: Parts Water (by vol.).. N-methyl-p-aminophenolsulfate 2.0 Sodium sulfite Hydroquinone 5 Borax 2 Water to make 1 liter.

TABLE 1 TABLE 3 Developing time Developin In 4 min. required to obtaintime (min. Adding developing relative sensirequired to amounts relativetivity of 100 Adding In 4 min. obtain the (g./l.) sensitivity Fog 7(min) 5 amounts relatige Develgprelative S9610- ar s sensi ivi in ositivit 1 Control 100 0. 04 1. 30 4 p y g g 7 y Imidazole 1 180 0. 04 1.33 2. Control. 0 100 0. 19 4. 00 4 D0 4 300 0 05 l. 36 1. 6 Imidazo1e 1140 0. 20 4.06 3 Do 4 250 0. 21 4. 08 2 10 Said results have beenattained wherein the silver halide EXAMPLE 3 contains fine grainedsilver chlorobromide and less than A high resolution plate, comprising asupport with ultra-fine grain silver iodobromide gelatin emulsion coatedthereon was subjected to development at 20 C. with developing solutionhaving following composition.

Developing solution C: Parts Water (by vol.) 800 l-phenyl-B-pyrazolidone0.5 Sodium sulfite 50 Hydroquinone 12 Sodium carbonate (NaCO H O) 60Potassium bromide 2.0 Benzotriazole 0.2 Water to make 1 liter.

This developing solution required 6 min. to develop the dry plate, butthe imidazole added developing solution shortened the developing time asshown in Table 2. On the other hand, 6 min. of development with theimidazole containing developing solution exhibited high sensitivity onthe dry plate.

Commercial microfilm comprising a support with a fine grain silverchlorobromide, gelatin emulsion coated thereon, was subjected todevelopment at 20 C. with a developing solution having followingcomposition.

Developing solution B: Parts Water (by vol.) 80 N-methylp-aminophenolsulfate 1.0 Sodium sulfite 75 Hydroquinone 9.0 Sodium carbonate (NaCO .H'O) 29 Potassium bromide 6.0

Water to make 1 liter.

The developing solution of E required 4 minutes to develop themicrofilm, but the addition of the imidazole to the developing solutionshortened the developing time as shown in Table 3. On the other hand, adevelopment time of 4 minutes with the imidazole added to the developingsolution produced a high sensitivity on the microfilm. Furthermore, thedeveloped silver grains in the picture were favorably fine and uniformaccording to the process of this invention using the imidazolecontaining developing solution.

1% of silver iodide, the particle size being smaller than 0.2 micron.

As this invention has been particularly illustrated with reference tothe examples, it will be clearly understood to one skilled in the artthat the scope of this invention is not to be restricted to the examplesand claims but that various alterations and modifications may be madewithout departing from the spirit of this invention.

Similar results have also been achieved using substituted hydroquinonesand specifically, chloro, bromo, methyl, dimethyl, phenyl and methylphenyl.

What is claimed is:

1. A method for processing an exposed silver halide black-and-whitephotographic material, wherein the silver halide grains are less than0.3 micron which comprises developing the photographic material with adeveloping solution comprising at least 1.0 part of hydroquinone as themain developing agent and at least 0.5 part of imidazole per one literof the developing solution.

2. The method of claim 1, wherein the concentration of hydroquinone andimidazole respectively is 1.0-20 grams/l. and 0.5-10.0 grams/l. byweight.

3. The method of claim 2, wherein the concentration of imidazole is from1.0-6.0 grams/l.

4. The method of claim 1, wherein the size of the silver halideparticles is less than 0.2 micron.

5. The method of claim 1, wherein the pH range is between 8.5 and 12.

6. The method of claim 5, wherein the pH ranges from 10-11.

7. The method as claimed in claim 1, wherein said silver halide containsfine grain silver chlorobromide and less than 1% of silver iodide,particle size of said silver halide being smaller than 0.2 micron.

8. The method of claim 5, wherein the silver halide is present in arange of from 10-70 mg./ 100 cm.

References Cited UNITED STATES PATENTS 2,324,123 7/1943 Weissberger9666.5 2,605,183 7/1952 Runyan 96-663 3,046,130 7/ 1962 Dersch et al.96-67 3,086,863 4/1963 Hunt et a1. 96-408 3,126,282 3/1964 Hunt 96-593,271,154 9/1966 Dersch et al. 96-66 3,335,009 8/ 1967 Rasch et a1.96-61 3,353,956 11/1967 Rogers et al. 96-29 3,397,987 8/1968 Luckey etal. 96109 3,576,633 4/1971 Henn et al 96-665 J. TRAVIS B ROWN, PrimaryExaminer M. F. KELLEY, Assistant Examiner U.S. Cl. X.R.

